JPS63228046A - V type light projecting device for visual inspection - Google Patents

Abstract

PURPOSE:To preclude halation and to obtain a sharp image by providing two parallel light emission parts distantly from a center surface, and projecting light from them slantingly to the center surface respectively so that a branch line is formed at a position to be inspected. CONSTITUTION:A body 10 to be inspected is set on a scanning table 12, which moves in synchronism with a CCD line sensor 18 to pick up a plane image of the body 10 to be inspected by the CCD camera 20 finally. Then the light emission parts 30a and 30b of a V type light projection device 24 shift from the center position right below the center 18. Namely, the end parts of optical fibers 32 arranged at the light emission parts 30a and 30b have their optical axes at an angle theta to the center surface 26 and illumination light beam emitted by them cross each other at the position to be inspected. Therefore, even if the body 10 to be inspected has a hole, etc., neither illumination light enters the sensor 18 directly. Consequently, the occurrence of halation is precluded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a light projection device that irradiates a strip of illumination light onto an object to be inspected in a transmitted illumination type visual inspection apparatus. This relates to a V-type floodlighting device that forms a shape and creates an intersection line at the measured position, so that even if there is a hole in the object to be inspected, the illumination light does not directly enter the line image sensor, making it difficult to cause halation. [Prior Art] There is a device that uses a transmitted illumination method to inspect the appearance of hybrid IC boards, printed wiring boards, and the like. For example, as shown in FIG. 3, this is arranged so as to face a scanning table 12 that conveys the object 10 to be inspected, and one surface (here, the lower surface) of the object 10 to be inspected, and is directed toward the object 10 to be inspected. It is composed of a light projecting device 14 that emits strip-shaped illumination light, and a COD camera 20 that is disposed facing the opposite surface (in this case, the upper surface) of the object to be inspected and is equipped with a lens 16, a CCD line sensor 18, and the like. Ru.

In the conventional technology, as can be seen from Fig. 3, the COD camera 20
is facing straight down, and the projector 11fflI4 is placed on its center plane.
The light emitting section is positioned upward and illuminates the inspected object 10 with transmitted light from directly below the center, and the light is efficiently collected by the CCD line sensor 18.

The object to be inspected 10 is set on a scanning table 12, which moves in synchronization with the CCD line sensor 18, and is finally captured as a planar image. In this way, appearance inspections of hybrid RC boards, various printed wiring boards, etc. are performed.

[Problems to be Solved by the Invention] However, in the prior art as described above, a light projecting device that generates one strip of illumination light is set at the center directly below the object to be inspected, and C
Since the light is emitted in the direction of the CD line sensor 18, if there is a hole such as a through hole in the object 10 to be inspected, the illumination light from the light emitting device 14 will directly enter the CCD line sensor 18, causing halation and distorting the image. There was a drawback that the accuracy deteriorated.

In order to solve the problem of deterioration of image accuracy due to this halation, the glass of the scanning table 12 may be made translucent to prevent illumination light from directly entering the CCD line sensor 18 even if there is a hole or the like in the object to be inspected. However, the semi-transparent glass weakens the illumination light and makes it difficult to obtain clear images.

The purpose of the present invention is to eliminate the drawbacks of the prior art as described above, to provide a sufficient amount of illumination light, and to prevent a line image sensor from causing halation even if a hole or the like is formed in the object to be inspected. To provide a light projection device for appearance inspection that is devised so as to be able to obtain a clear image without causing any disturbance.

[Means for Solving the Problems] The present invention is a light projection device used in a transmission illumination type visual inspection device using a line image sensor. In order to achieve the above-mentioned object, the present invention includes two parallel light emitting sections located away from the central plane, and the band-shaped illumination lights from them are inclined with respect to the central plane and intersect at the inspection position. Like making V
It is configured to project light onto the mold.

[Function] In the present invention, since the light emitting part of the floodlight device is provided at a position away from the center plane that includes the line image sensor, the strip-shaped illumination light is directly emitted even if the object to be inspected has a hole or the like. It does not enter the line image sensor.Therefore, even if the scanning table is not made translucent, halation is less likely to occur, and the object to be inspected can be illuminated with a sufficient amount of illumination light to obtain a clear image.

Furthermore, since the strip-shaped illumination light is projected in a V-shape, shadows are less likely to be formed, unlike the case where the strip-shaped illumination light is applied only to one side.

[Example] FIG. 1 is a schematic explanatory diagram of an appearance inspection apparatus using a ■-shaped projector according to the present invention, and FIG. 2 is a perspective view showing an example of a V-shaped projector. Since the basic configuration of the visual inspection device may be substantially the same as that of the conventional device shown in FIG. 3, corresponding parts are given the same reference numerals to make the explanation easier to understand.

An object to be inspected 10 such as a hybrid IC board or a printed wiring board is placed on a scanning table 12 and driven in the direction of the outlined arrow. In this case, unlike the prior art, the glass of the scanning table 12 may be transparent. Directly above the scanning table 12 are a lens 16 and a CCD line sensor 18.
A CCD camera 20 is installed. A V-type projector W, 24 according to the present invention is provided directly below the inspection object 10 so as to face the lower surface of the object 10 .

This V-type projector 24 has a shallow V groove 2 in the center of its upper surface.
8 is formed, and two parallel groove-shaped light emitting portions 30a and 30b are symmetrically formed on the double-ended slopes of the V-groove at positions away from the center plane of the CCD camera 20. This groove-shaped light emitting section 30
A large number of optical fibers are lined up and buried in the areas a and 3σb with their end faces aligned, and the optical fibers are bundled and guided to the light source section. The bundled optical fibers are designated by the reference numeral 32. Light emitting part 30a.

The optical axes of the ends of the optical fibers lined up in 30b are each inclined at an angle θ with respect to the central plane 26,
The strip-shaped illumination light emitted from them is the position to be inspected (i.e. C
The CD camera 20 is attached so as to intersect at a line that includes the center plane 26 of the CD camera 20 and intersects the object to be inspected.

As in the conventional visual inspection apparatus, the object to be inspected 10 is set on the scanning table 12, the scanning table 12 moves in synchronization with the CCD line sensor 18, and finally the COD
The camera 20 captures the object to be inspected as a planar image. In the present invention, since the light emitting parts 3Qa and 30b of the ■-shaped floodlighting device are shifted from the center position directly below the CCD line sensor 18, the illumination light is directly directed to the CCD line sensor 18 even if the object 10 to be inspected has a hole or the like. It never enters. For this reason, it becomes difficult for sagging to occur. Furthermore, since the light is projected from both sides, that is, in a V-shape, unlike the case where only one side is projected, there is no shadow, and the reliability of the external appearance inspection is also improved.

Although a preferred embodiment of the present invention has been described in detail above, it is to be understood that the present invention is not limited to only such a configuration. In the above embodiment, a shallow V-groove is provided at the center of the top surface, but the top surface may be flat as long as the light emitting portion has a predetermined angular width.

[Effects of the Invention] As described above, in the present invention, two parallel light emitting parts are provided at positions offset from the center plane of the line image sensor, and the strip-shaped illumination light is obliquely inclined with respect to the center plane. Since the irradiation is performed so as to create intersecting lines at the inspection position, shadows are less likely to be formed, and even if the object to be inspected has a hole, the illumination light will not directly enter the line image sensor, preventing the occurrence of halation. However, there is no need to use translucent glass for the scanning table, and the amount of light generated by the light emitting section can be used effectively, resulting in an excellent overall effect of being able to obtain very clear images.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing an example of a visual inspection device using a V-type projector according to the present invention, FIG. 2 is a perspective view showing an example of the V-type projector according to the present invention, and FIG. The figure is an explanatory diagram showing an example of a conventional technique. DESCRIPTION OF SYMBOLS 10... Inspection object, 12... Scanning table, 18.
...CCD line sensor, 20...CCD camera, 2
4...V-type projector, 26... Center plane, 30a. 30b... Light emitting part, 32... Optical fiber, 34.
・Intersection line. Representative Shigeru Minoru Figure 1 Figure 3 Figure 2 3δ0

Claims (1)

[Claims] 1. It has two parallel light emitting parts located away from the center plane, and the band-shaped illumination light from them is projected in a V-shape so that it is inclined to the center plane and intersects at the inspected position. A V-shaped projector for visual inspection that emits light.